It makes me Angry when someone thinks that they know what they are talking about or maybe they don't but for the sake of being a smart ass they make some crap up. Those people make me angry.
That and when my I-pod runs out of charge midway through a song, I hate ending a song early.
I have a lot more but i'll end with just one more.
When a manga i am interested in doesn't get a new chapter for months and It makes me think it is never going to happen, but of-course then it comes out in like the next week and i am really happy.

i wouldnt say i get angry more just irritated. normally when people ask me the same question too many times. or when my daughter tries to tell me knock knock jokes only cause she doesn't understand the point of a knock knock joke yet so instead i get something like
dru- knock knock
me -who's there?
dru- .......ummm.....uh....fish...
me- okay fish who?
dru- a fish falling out of the sky and hitting you in the face! hahahahahahahaha!
me- ....well alright then....

but probably the thing that makes me closest to being pissed off is when your friends up and dessert you in your time of need after you have been there for them through every crisis of there life and suddenly when the shoe is on the other foot they are suddenly to busy to be bothered to help you in the same way. its just selfish
oh and when people who owe me money never pay me back :/

My own mistakes and stupidity.
When people are so close-minded they refuse to accept any other ideas or possibilities.
When people are judgmental and dislike someone before even knowing them. (I'm sometimes guilty of this too, I try not to be)
When people brag about being right or better than others.
When people pretend to care about you, but really don't.

The only thing that really bugs me anymore is when people ask me "Whats wrong?" I am a generally quiet person and i guess i have a angry face or something? But never once has someone asked me "Whats wrong?" when anything was -3- its really annoying. I'M FINE I JUST DON'T WANT TO TALK TO YOU!

Oh my god. Don't even get me started. What pisses me off is having a whole bunch of ingredients to make food but no food to actually make, leaving doors open, people making noises while eating food and YES when I'm obviously angry and being antisocial and people try to talk to me I just, nope. Please don't. Or not being able to continue a conversation with someone because they just aren't putting much effort or waiting forever for their one worded reply knowing full well that they read it. Or when I'm hungry or tired. I'm just automatically pissy.